Effect of System Pressure and Solute Concentration on Fertilizer Injection Rate of a Venturi for Fertigation

Venturi injector is a commonly used device for fertilizer application through drip irrigation. The injection rate of a venturi injector mainly depends upon the suction created due to the difference between its upstream and downstream pressures. A commercially available venturi was evaluated for injection rate under the range of operating pressures from 1.0 to 2.0 kg.cm-2 using normal irrigation water and fertilizer solution. Maximum injection rate of the venturi with irrigation water was 106.4 l.h-1 at operating pressure of 2.0 kg.cm-2. Maximum injection rate (105.8 l.h-1), when urea fertilizer dissolved in irrigation water in the ratio of 0.25:1 (urea: water) was at the upstream and downstream pressure of 2.0 kg.cm-2 and 0.1 kg.cm-2, respectively. However, for muriate of potash (MOP) dissolved in irrigation water in the ratio of 1:1 (MOP: water), minimum injection rate of venturi was 1.44 l.h-1 at upstream pressure of